DAIRY FARMING — DAIRYING. 1007 



Preservation of milk before skimming-, L. Marcas and C. Huyge {Bill. Agr. 

 [Brussels], 21{1905), No. 6, pp. 1111-1116 . Practical methods of straining, cooling, 

 etc., are mentioned and their value illustrated by experimental data. 



Action of the ultra-violet rays on milk, \. < . u:m i; and A. Ilnx in /.*, v. Gen. 

 Lait, 5 ( 1906), No. //, pp. ?52, US.; Milchw. ZentbL, / \ 1906), No. S, pp. 119, 120).— 

 Attempts to sterilize milk by means of the ultra- \ iolel rays were unsuccessful. The 

 authors, however, considered it possible, by more intense rays than those used and 

 longer exposure, to sterilize milk in this way, although the method would no1 

 apparently be capable of practical application. 



The significance of streptococci in milk, P. G. Heinemann {Jour. Infect. Dis- 

 eases, 3 I 1906), No. .', pp. 17S-182,pls. 3). — This is the full reporl of investigations of 

 which an abstract has already been uoted I . B. R., L7, p. BOO , The three plates 

 Bhow the growth of Streptococcus pyogene s and S.lacticus from two sources on scrum 

 broth, lactose broth, and litmus milk. 



Streptococci and leucocytes in milk, W. G. >w \<,i; {Jour. Hyg. [Cambridge], 

 6 ( 1906), No. 2, pp. 123-138).— The methods employed are described. In the count- 

 ing of leucocytes the author makes use of the Thoma-Zeiss blood-counting apparatus 

 in much the same manner as previously described by Doane I E. S. R., 17. p. 181 l. 

 One cc. of milk is diluted with aboul 20 cc. of Toisson's fluid and centrifuged for 10 

 minutes at 1,800 revolutions per minute. The cream is then broken up with a glass 

 rod and the mixture is again centrifuged for a second period of 10 minutes after 

 which the fluid is aspirated off to the I <•<•. mark. Alter thoroughly mixing the 

 remaining 1 i-c a sufficient quantity is placed in the Thoma-Zeiss apparatus and the 

 preparation examined in the same way as in the enumeration of blood corpuscles. 



When the counting is done by flelds, the author estimates the number of leucocytes 

 per cu. mm. of milk by the formula - '' - - x , in which y equals the average number 



of leucocytes per field, and d the number of squares of the blood counter u hich jusl 

 spans the diameter of the field. The methods of counting leucocytes in dried and 

 stained preparations used by Stokes and others were found very unsatisfactory. 



Samples of milk from individual cows and also of mixed milk were examined. 

 The results showed that streptococci were very frequently present. In the milk of 

 individual cows streptococci were present in 4l\ per cent of the samples when 1 <•<•. 

 of milk was used in the examination, and invariably present in the mixed milk. In 

 all they were present in 45 out of 68 samples examined, or tit; percent. As all of 

 the cows were apparently healthy, the results are considered as showing clearly that 

 streptococci as a class are very prevalent in pure milk. The study of the streptococci 

 isolated showed 12 types, the characters of which are given. 



Leucocytes were present in every sample, ranging in numbers from .".."> to 1,380 per 

 cu. mm. in samples from individual cows and from 21 to 1,980 in mixed milk. Con- 

 trary to conclusions reached hy Merge y ( K. S. I;., pi, p. 699), the author's results 

 show- no connection between the numbers of pus cells and streptococci. The author 

 states that he can not differentiate between a leucocyte and a pus cell, and that he is 

 not prepared at present to lay down an arbitrary standard as to w hat number of leu- 

 cocytes in milk per cu. mm. is to he designated pus. 



Bacillus cm/;, considered as a definite indicator of contamination, was found in 1 7."> 



pei- cent of the samples of milk from individual cows, in .".<; per cent of the samples 

 of mixed milk examined within :'. hours from the time of milking, and in 94 per cut 

 of mixed and market samples not examined promptly. 



The leucocyte test of milk, R. Trommsdorff (Munchen. Med. Wchnschr., 63 

 (190'i), No. 1 .'. ]>/>. 541-649). — In estimating the leucocyte content. 5 cc. of milk was 

 centrifuged and the sediment measured in a graduated sedimentation tube. 



In the majority of cases the leucocyte content determined in this way varied from 

 mere traces to 0.4 cc. per liter. In some instances, however, the sediment amounted 



